Wallops Island Causeway Bridge 10-06-16 Inspection Report.pdf

In-depth Inspection of

Wallops Island Causeway Bridge

Over Cat Creek

Goddard Space Flight Center Wallops Flight Facility

October 2016

Report Prepared For:

Federal Highway Administration Eastern Federal Lands Highway Division Bridge Inspection and Management Program 21400 Ridgetop Circle Sterling, Virginia 20166

Report Prepared by:

IN-DEPTH INSPECTION REPORT

Structure: Wallops Island Causeway Bridge Date Inspected: October 6, 2016

TABLE OF CONTENTS

General Photos .............................................................................................................................. 3-8

Commentary ................................................................................................................................. 9-22

Overview

Structure Description

Structure Orientation

Structure Access and Inspection

Summary of Findings ............................................................................................................................. 10-14

Recommendations ................................................................................................................................. 14-18

Cost Estimate ........................................................................................................................................ 19-22

Appendix A – Component Detail Sheets ......................................................................................... A1-109

Abbreviations and Symbols ........................................................................................................................ A1

Top of Deck.............................................................................................................................................. 1-21

Reflected Deck ...................................................................................................................................... 22-44

Beam Elevations .................................................................................................................................... 45-87

Substructure Elevations ....................................................................................................................... 88-108

Fender System

Appendix B – Deficiency Photos .......................................................................................................... 1-44

Appendix C – General Underside Photos ........................................................................................... 1-21

Appendix D – Load Rating Summary Sheet ........................................................................................ 1-3

Appendix E – Load Rating Axle Spacing Chart

Appendix F – Structure Inventory and Appraisal (SIA) Sheet ......................................................... 1-2

Appendix G – FHWA Revised Estimate

General Photos

LOOKING EAST TOWARD WALLOPS ISLAND

LOOKING WEST TOWARD SECURITY GATE

NORTH (DOWNSTREAM) SIDE

SOUTH (UPSTREAM) SIDE

GENERAL TOPSIDE VIEW LOOKING EAST

GENERAL VIEW OF RAILING, NORTHWEST CORNER

GENERAL UNDERSIDE VIEW LOOKING EAST, SPAN #15

GENERAL UNDERSIDE VIEW LOOKING EAST, SPAN #11

GENERAL VIEW OF ABUTMENT A

GENERAL VIEW OF PIER #19, WEST SIDE

UPSTREAM CHANNEL

DOWNSTREAM CHANNEL

COMMENTARY

OVERVIEW:

Clark Nexsen, Inc. was tasked by the Federal Highway Administration, Eastern Federal Lands Highway Division, Bridge Inspection and Management Program to perform an in-depth inspection of the Wallops Island Causeway Bridge over Cat Creek at the Goddard Space Flight Center, Wallops Flight Facility.

The Wallops Flight Facility is located in Accomack County, Virginia on the Delmarva Peninsula. The Flight Facility is owned by the National Aeronautics and Space Administration (NASA).

The purpose of this inspection was to identify and document all areas of deterioration across the entire structure, above the waterline. Then, after determining the range and magnitude of deterioration, provide recommendations and costs to extend the useful life of the structure at its current level of operations.

The inspection was conducted Monday, October 3, 2016 through Thursday, October 6, 2016 by A. Dwayne Mitchem, P.E. and Walter R. Fairlie, P.E. of Clark Nexsen, Inc.

STRUCTURE DESCRIPTION:

Wallops Island Causeway Bridge is a twenty-one span bridge, consisting of twenty 60’ long spans and one 83’-6” long span totaling 1283’-6” long. Each typical 60’ long span is constructed of a cast-in-place concrete deck supported by four prestressed concrete beams on concrete piers. The 83’-6” span (Span #11) is of similar construction, but has five beams.

The bridge provides the only access to NASA’s island facility. There is a weight limit sign near the security gate at the west approach that restricts the weight of unpermitted vehicles crossing the bridge onto the island.

According to drawings provided to the inspectors, the Wallops Island Causeway Bridge was constructed in 1959. The structure was rehabilitated in 1986, including shotcrete repairs to the prestressed concrete beams.

Subsequent to the rehabilitation, the beams in Spans #8 and #11 were strengthened by the installation of post-tensioning strands on the underside of the bottom flanges. Four post-tensioning strands were installed on each beam in Span #8 and two on each beam in Span #11. Each strand consists of a sheathed strand surrounded by a grout filled plastic duct. An anchorage assembly was installed near each end of each beam and covered with a protective layer of shotcrete. Construction documents for this strengthening project were not available to the inspectors. The structure was rehabilitated again in 2013, primarily consisting of FRP repairs to the prestressed concrete beams. The existing shotcrete layer was removed from the underside of several beam bottom flanges, and the entire bottom flange was wrapped with glass FRP, then coated with epoxy. Some beams were further strengthened with a layer of carbon FRP contained by the glass FRP.

Additionally, all plastic post-tensioning ducts were wrapped with glass FRP as well. Random minor concrete repairs were also made to the beam webs, closure pours, and at isolated locations on the deck and substructure. The as-built plans for this rehabilitation were made available to the inspectors prior to the inspection.

STRUCTURE ORIENTATION:

Wallops Island Causeway Bridge is sited on an east-west alignment with Abutment A at the west end and Abutment B at the east end. Spans #1-#21 and Piers #1-#20 are numbered from Abutment A. Cat Creek, which is tidal in nature, is oriented north-south with a navigable channel below Span #11. Beams are numbered #1-#4 from the north in Spans #1-#10 and #12-#21. Beams are numbered #1-#5 from the north in Span #11.

STRUCTURE ACCESS AND INSPECTION:

The underside of the structure was accessed using an Aspen Aerial A-62 Inspection Vehicle owned and operated by All Access Rigging Company. Spivey Rentals, Inc. was onsite performing maintenance of traffic operations which included an alternating lane flagging operation. A visual and tactile inspection was performed on all exposed surfaces of the structure. The concrete was sounded with masonry hammers to detect areas of delamination. Where areas of cracking, delamination, or spalling were detected, the dimensions of the deteriorated areas were documented along with the locations.

SUMMARY OF FINDINGS:

Below is a summary of the findings of this inspection. Detailed findings are contained in the component detail sheets in Appendix A. Photos for specific deficiencies are located in Appendix B. General underside photos for all spans are located in Appendix C.

DECK

Overall, the general condition of the deck is considered Satisfactory (NBI Condition Rating = 6). See below for additional comments relating to the deck.

Deck Slab:

Typically, the deck surface has minor scaling throughout and isolated minor transverse cracking. See Photos #1 and #2. The corners of the deck exhibit minor random cracking at several locations, some with efflorescence. See Photos #3 and #4. Random areas of minor to moderate delamination, spalling, and concrete repairs are also located in the deck surface, primarily along the deck headers; some repaired areas are delaminated as well. See Photos #5, #15, and #18. The deck headers also have minor edge spalling at random locations along the expansion joints, but up to 4” wide x 2-1/2” deep at isolated locations. See Photos #12, #13, #16, #19, and #21 – #23. The lane markings on the deck surface are faded or have been removed throughout. See Photos #5 and #18.

The entire deck underside is damp and discolored (green). See Photos #24 – #26. Typically, there is up to 25 SF of faint map cracking with moisture stains on the underside, between the beams, near the piers. See Photos #24 and #26. The cracking is slightly more prominent (hairline) with efflorescence on the underside of the overhangs at the piers, as well as at locations of deck drain penetrations. See Photos #27 and #28.

Areas of delamination, honeycombing, and spalling up to 1 ½” deep with exposed rebar are located at isolated locations on the deck underside; isolated areas appeared to be chipped out for repairs. See Photos #46 and #62. Isolated areas of concrete and shotcrete repairs also exist on the deck underside; large areas of shotcrete are delaminated in Span #17 and a smaller area in Span #1. There is heavy vine growth on the north deck overhang in one location in Span #1. See Photo #41.

Expansion Joints:

The pourable expansion joint sealant in the curbs and parapets is deteriorated throughout. See Photo #6.

The pourable sealant in the deck expansion joints has isolated areas of adhesion failure, typically at spalls in the deck headers. See Photos #10, #12, #13, #16, #19, and #21 – #23.

The original joint filler material between the beam ends and closure pours, below the deck, is brittle and deteriorated throughout; the material has fallen out at some locations. See Photos #29 and #30.

Curbs:

The curbs have been coated with epoxy in the past. Hairline to 1/32” wide x up to 2’ long random cracks are beginning to show through the epoxy at isolated locations. There are areas of delamination on the south curb in Span #3 and north curb in Span #16. The metal access panels in the curbs are missing screws at random locations; some panels are missing numerous screws. See Photo #17.

Parapets and Railings:

The parapets have also been coated with epoxy in the past. Typically, there is up to 5 SF of hairline to 1/16” wide map cracking with efflorescence, rust stains, and delamination on the exterior face of the parapets at the piers and isolated locations of minor cracking elsewhere. See Photo #7. There is an additional area of delamination on the south parapet in Span #3.

The bottom rail end caps over the piers on the south side have been removed for cable installation; bottom rails remain open at these locations. See Photo #8. The bottom rail expansion sleeve is torn full circumference at Piers #15 and #19 on the north side. See Photo #20. The railing toggle bolts are also missing at isolated locations and there is isolated areas of damage to the rails. See Photo #14.

Drains and Drainage:

The deck drains are partially to fully clogged at random locations. See Photo #9. There is surface rust and rust scale on the drain boxes below the deck at the concrete penetrations. See Photo #42.

Utilities:

Two metal conduits and one insulated sewer line run along the north side of the bridge for full length. Surface rust typically exists throughout the utility connection hardware and metal conduit threads at the connection fittings. See Photos #27 and #31. Additionally, there are two smaller metal conduits that run along the north side of the bridge for the east half only. A utility junction box and conduit fitting is open with wires exposed on the exterior side of the north parapet in Span #21.

Four epoxy coated metal conduits and one insulated water line run along the south side of the bridge for full length. Typically, there is surface rust on the ends of the metal conduits adjacent to the connection fittings where epoxy does not exist. See Photo #32. Very isolated u-bolts and/or nuts are missing from conduit-to-hanger connections. At three locations, sections of the outer sheathing for the water line is missing with surface rust, rust scale, and up to 100% section loss to the metal plates of the water line expansion joint assembly at two of those locations. See Photo #45.

Two electrical conduits have been removed from the north sidewalk in the past.

SUPERSTRUCTURE

Overall, the general condition of the superstructure is considered Satisfactory (NBI Condition Rating = 6).

See below for additional comments relating to the superstructure.

Bearing Devices:

The elastomeric bearing pads have minor cracking at isolated locations with pads being over compressed at random locations. See Photos #33 and #34.

Beams (including recent beam strengthening project):

The underside of most beam bottom flanges have been covered with a layer of shotcrete that is approximately 1-1/2” thick, consistent with the 1986 rehabilitation plans; however, due to the presence of a 1” fillet along both edges of the bottom flanges, this layer appears to be approximately 2-1/2” thick when viewed from the side of the beam. The limits of the shotcrete layer are shown on the reflected deck component detail sheets as a dark gray shading. The plans indicate that the shotcrete is reinforced with welded wire fabric and, when considered as a unique element, is performing very well. The entire bottom flanges, including the shotcrete repairs, have been coated with epoxy in the past; the epoxy is flaking throughout. See Photo #35 and photos in Appendix C.

In many locations, it appears that the entire shotcrete layer has separated from the beams. This was typically observed as a crack along the edge of the bottom flanges at the interface between the shotcrete and original beams. These areas were sounded with a masonry hammer to establish the limits of the delamination.

However, due to the thickness and mass of the shotcrete layer, in some cases it was very difficult to detect the delamination, even with robust sounding. It is likely that this deterioration is the result of poor surface preparation prior to the application of the shotcrete. Delaminations of this type are noted on the reflected deck component detail sheets as having a height of less than or equal to 2-1/2”. See Photo #47.

In numerous locations, the deterioration extends up into the side of the bottom flange of the original beams.

In some cases, this appears as a crack running along the face of the bottom flange that sounds delaminated when struck with a hammer. Delaminations and spalls of this type are noted on the reflected deck component detail sheets as having a height of greater than 2-1/2”. See Photos #40, #43, #53, #57, and #60. At one location in Span #9 and another in Span #13, the concrete of the original bottom flange is moderately deteriorated, but is being restrained and held in place by the shotcrete layer. See Photos #50 and #55.

It appears the concrete in Span #13 had been chipped away for observation during a previous inspection, and the prestressing was galvanized.

At isolated locations, there are areas of delamination and spalling of the bottom flanges where there is no shotcrete. These areas are generally located near the bearings, and there is some exposed reinforcing, but no exposed prestressing strands. See Photos #56 and #68.

On several beams, the shotcrete layer was removed from the underside of the bottom flanges, and the entire bottom flange was wrapped with glass FRP, then coated with epoxy. Some beams were further strengthened with a carbon FRP (not visible) contained by the glass FRP. Additionally, all plastic post-tensioning ducts in Spans #8 and #11 were wrapped with glass FRP as well. The locations of the FRP repairs are shown on the reflected deck component detail sheets as a light gray shading. The FRP repairs appear to be adequately adhered to the beams and no deficiencies were observed in the repairs while inspecting these elements. See photos in Appendix C.

The post-tensioning system in Spans #8 and #11 continues to function as intended with only isolated deficiencies remaining since the most recent repairs were made. As stated above, all plastic post-tensioning ducts have been wrapped with glass FRP since the last inspection. Typically, a small section of the ducts remain unwrapped where they transition to a shotcrete covering near the anchorage assemblies. See Photo #54. Most of the previously noted splits in the ducts are no longer visible, as they have been covered by the FRP wrap, but a few minor deficiencies are still visible near the anchorage assemblies. In Span #8, the southernmost duct on Beam #1 is missing a grout port cap at the anchorage near Pier #7. Also in Span #8, a 1” diameter hole exists in the FRP wrap on the northernmost duct of Beam #1 near mid-span exposing a broken section of conduit with one tendon visible; no noteworthy deficiencies where observed on the tendon.

See Photos #51 and #52. A radial split still exists on the southernmost duct of Beam #1 at the anchorage near Pier #10 in Span #11. See Photo #54.

At isolated locations in Span #8, the shotcrete covering the anchorage assemblies is delaminated. At the west anchorage of Beam #4 in Span #8, the spalling at the corner of the protective shotcrete has increased in size since the last inspection and the surface of the anchorage is exposed and rust scaled. See Photo #48.

Additionally, the corner of the protective shotcrete at the west anchorage of Beam #3 in Span #8 is also spalled with the surface of the anchorage exposed.

Typically, there is up to 5 SF of hairline map cracking with efflorescence on the exterior side of the exterior beams webs at the top corner over the piers. See Photos #36 and #37. Numerous areas of delamination and isolated surface spalling up to 1” deep were also observed on the beam webs due to insufficient concrete cover over the reinforcing stirrups. These areas are primarily in the thickened portion of web at the ends of the beams, but are also at random locations elsewhere. See Photos #38 and #64 – #67. In many locations these areas have been repaired with concrete or covered with shotcrete in the past; however, most of the shotcrete is delaminated.

Diaphragms:

Numerous diaphragms have been repaired with shotcrete in the past; hairline map cracking and some delamination throughout the repairs. Additionally, isolated unrepaired diaphragms have horizontal cracking up to 1/16” wide with rust stains, small areas of delamination and spalling up to 1” deep with exposed rebar, and some concrete repairs. See Photo #39.

The cast-in-place concrete closure pours at the ends of the beams have areas of delamination and spalling at the bottom at random locations. In many places these areas have been repaired with concrete in the past;

however, some of the repairs have since delaminated or spalled. See Photos #37, #44, #49, #58, #59, and #63. This deterioration was found to be more prevalent at the fixed end of the beams where steel dowels anchor the beams to the bearing seats. All of these areas occur beyond the back edge of the bearing pads.

The closure pour delaminations and spalls are located at the bottom of the beam unless otherwise noted.

SUBSTRUCTURE

The results of the most recent underwater inspection conducted by Collins Engineers, Inc. in January 2015 were considered when determining the condition of the substructure. Above the waterline, the entire substructure has been coated with epoxy in the past; the epoxy coating is flaking throughout the abutments.

See Photo #72. Overall, the general condition of the substructure is considered Satisfactory (NBI Condition Rating = 6). See below for additional comments relating to the substructure.

Abutment Breastwalls:

Hairline x up to full height vertical cracks exist at random locations on both breastwalls.

Abutment Bearing Seats:

The Beam #1 bearing seat at Abutment A has 1/16” wide horizontal cracking with rust stains and minor delamination and spalling not affecting the bearing capacity. See Photo #69.

Abutment Backwalls:

There are hairline x up to full height vertical cracks, typically 2 to 3 per bay, in the Abutment A backwall; two cracks are up to 1/16” wide. See Photo #39. Hairline map cracking with efflorescence exists throughout the Abutment B backwall.

Abutment Foundations:

Hairline to 1/32” wide map cracking is located throughout the face of the abutment footings; cracks are up to 1/8” wide with rust stains at Abutment B.

Abutment Wingwalls:

Hairline random cracking and one minor diagonal crack exists throughout the south wingwall at Abutment A, primarily extending from the utility penetrations.

Abutment Erosion and Scour:

Minor to moderate erosion (up to 2’ wide x 1’ deep) was observed along the Abutment B footing with undermining of the footing up to 1’ under at two locations; the erosion also extends under the north drainage trough for the slope protection. See Photo #71. However, it should be noted the abutment footings are founded on piles.

Abutment Slope Protection:

A 5’ diameter x 2’ deep erosion hole is located at the bottom of the drain trough on the south side of the Abutment A slope protection with some concrete blocks (hardened bags of concrete) displaced. See Photo #70. The bottom three rows of the concrete slope protection blocks are displaced for full with of the Abutment B slope protection, totaling approximately 300 SF.

Cylinder Piles:

Hairline x up to 6’ long vertical cracks typically extend from the top of the piles and are spaced 8” to 12” apart.

The cracks are beginning to show through the epoxy and some have efflorescence. Several cracks have been sealed with additional epoxy in the past, but some cracks are showing through again; sealed cracks are more prominent at the east end of the structure. See Photos #72 and #73.

Concrete patching on top of the piles is typically delaminated up to 36” long x 8” wide adjacent to the caps;

condition appears as-built. See Photo #74. Random delamination and spalling up to 1” deep with up to 50% section loss to exposed rebar and isolated prestressing strands also exists on the vertical face of the piles, primarily at top, but isolated locations elsewhere. See Photos #73 and #78. The upper portion of the piles at Piers #10 and #11 have been repaired with fiberglass jackets in the past.

For deficiencies located at or below the high waterline, refer to the most recent underwater inspection report.

Pier Caps and Bearing Seats:

There is random hairline cracking up to 2’ long at isolated locations on the pier caps and bearing seats.

Hairline to 1/32” wide horizontal and map cracking exists throughout isolated bearing seats with rust stains at very isolated locations. See Photo #79.

Typically, there is hairline map cracking throughout the end 2 LF of the caps (including underside of overhang), some with efflorescence. Numerous cracks have been sealed with additional epoxy in the past, but several cracks are showing through; sealed cracks are more prominent at the east end of the structure.

Some areas of unsealed map cracking is up to 1/8” wide with efflorescence and/or rust stains. It is not uncommon for the cracking on the ends of the caps to be accompanied by moderately sized areas of delamination and isolated spalling. See Photos #75, #77, and #81. Random areas of delamination and concrete repairs also exist elsewhere on the caps. See Photo #76. There is one area of shotcrete repair on the Pier #18 cap, with a small section of that repair delaminated. See Photo #80.

Pier Erosion and Scour:

No noteworthy deficiencies pertaining to erosion or scour were observed during the most recent underwater inspection.

CHANNEL

No noteworthy deficiencies pertaining to the channel or channel protection were observed during the inspection. The general condition of the channel is considered Very Good (NBI Condition Rating = 8). See below for additional comments relating to the fender system.

Fender System:

Typically, there is 1/16” wide to 1/4” wide checking throughout the timber dolphin piles. See Photo #83.

Moderate corrosion with less than 10% section loss exists on lower dolphin steel wire wraps. See Photo #82.

Typically, the timber wales have checking up to 1/8” wide throughout. Loss of galvanization with minor surface rusting exists on the lower 3’ of steel plumb piles at the waterline; moderate corrosion with up to 1/16” section loss to hardware securing 4th, 5th, and 6th timber wales (from top) to the steel plumb piles. See Photos #84 and #85. Additionally, there is loss of galvanization with moderate corrosion (up to 1/16” section loss) to the lower 3’ of steel ladders and connection angles along waterline. See Photo #86.

APPROACHES

The approaches have been repaved with asphalt in recent years. A 2’ wide strip of asphalt along Abutment A was unpaved, and remains rough and deteriorated. See Photo #10. A 4’ wide strip of asphalt along Abutment B was unpaved, and remains in fair condition with an 18 SF concrete repair in the EBL. There is spalling up to 1-1/2” wide x 1” deep for 4 LF total in the Abutment B approach slab header along the deck expansion joint. See Photos #22 and #23.

The weight limit sign at the west approach is leaning and faded. See Photo #11.

RECOMENDATIONS:

Construction of the first prestressed concrete beam bridge in the United States was completed in 1950. This structure, built in 1959, exhibits similar deterioration as other structures built during the early years of prestressed concrete construction. However, the repair of each type of deterioration must be considered with the goal of maintaining the structure for 10 to 15 years in mind.

DECK

Deck Slab:

If not repaired, the delaminated areas in the deck surface will eventually break up, spall, and expose rebar.

These deficiencies will not only affect rideabilitly, but allow further deterioration of the deck concrete and steel due to the surrounding coastal environment. The delaminated and spalled areas of the deck slab and headers should be chipped out to a depth below the top layer of rebar, and the concrete cast back to original dimensions. Then, a wearing surface should be applied to prevent future delamination and spalling due to water intrusion through cracks in the deck surface.

Similarly on the deck underside, the areas of delamination, honeycombing, and spalling should be repaired with concrete to prevent further deterioration. These concrete repairs will simply prevent the condition of the deck from worsening, and help maintain its current load carrying capacity as well. The vine growth on the north deck overhang in Span #1 should also be removed to keep additional moisture away from the deck underside.

Expansion Joints:

The deck expansion joints, including sections within the curbs and parapets, should be routinely cleaned and resealed as necessary to prevent water from penetrating the deck ends, and/or leaking onto the superstructure and substructure below. In some cases, the deck header spalls may need to be repaired first.

This is a basic, low cost repair that can drastically increase the life cycle of a structure and prevent additional problems from occurring in the future.

Curbs:

The areas of delamination on the curb in Spans #3 and #16 should be repaired in an effort to prevent future spalling. A repair of this nature is not needed to prolong the life cycle of the structure, but may be lumped together with additional work of this type if desired. Furthermore, the missing screws in the access panels on the topside of the curbs should be replaced to prevent water leakage into the utility areas of the curbs, and potentially into the deck overhangs.

Parapets and Railings:

The deterioration of the parapets at the joints over the piers can possibly be attributed to water intrusion in and around the ends of the utility conduits within the parapets. This condition is typical over each pier, but does not necessarily have the ability to impact the load carrying capacity of the structure in the near future.

Water has begun to percolate into the edges of the deck, as minor cracks with efflorescence were observed at the corners of the deck surface adjacent to the curbs and on the underside. The deterioration process has begun, but a condition that would impact structural integrity of the deck is not probable within the next 10 to 15 years. The ability of the parapet to withstand the impact of an errant vehicle is not yet suspect either. It is our opinion that widespread concrete repairs of this nature would be costly and not extend the life of the bridge any meaningful amount of time.

Isolated railing toggle bolts are missing throughout, as well as numerous railing end caps missing on the south railing and two expansion sleeves torn on the north railing. None of these deficiencies affect the strength or serviceability of the railing, but should be repaired during the course of routine maintenance.

Drains and Drainage:

The deck drains should be continuously cleared at a regular interval to prevent water from ponding and infiltrating the deck surface or any construction joint between deck elements. This is another low-cost maintenance item that can significantly extend the operational life of a bridge.

Utilities:

Typically, utility related problems do not affect the strength or serviceability of a structure. With that said, the following repairs are being recommended to prevent an interruption of service at the Wallops Flight Facility.

On the north side of the bridge, the broken/missing utility conduit cover plates should be replaced on exterior side of north parapet in Span #21 to prevent water from entering the conduit. On the south side, the missing u-bolts and nuts should be replaced to ensure full capacity of the connections. Additionally, the missing water line sheathing should be replaced to properly protect the water line, and the expansion joint assemblies repaired as necessary.

SUPERSTRUCTURE

Bearing Devices:

The elastomeric bearing pads are generally in fair condition and do not require any maintenance or repairs at this time.

Beams (including recent beam strengthening project):

There are many areas where the shotcrete layer has separated from the underside of the bottom flanges. It is likely that this is the result of poor surface preparation prior to the application of the shotcrete and not related to corrosion of the prestressing strands. No repairs are recommended for these areas. It is our opinion that repairing these areas will be difficult and will not extend the life of the structure significantly.

There are numerous areas of delamination and spalling that extend up into the side of the bottom flanges of the original beams. It is our opinion that this deterioration is the result of the stresses induced by the volume change of the steel resulting from the corrosion process. We recommend repairing all locations where delamination and spalling along the edges of the beam bottom flanges extends into the original beam (noted as greater than 2-1/2” high where shotcrete is present). Due to the questionable strength of the bond of the shotcrete to the bottom flange, we recommend saw cutting the full thickness of the shotcrete layer beyond the limits of the intended repair to minimize the risk of causing additional delamination of the shotcrete during the concrete removal process. The concrete of the original beam should then be chipped out to beyond the corroded reinforcing, the strands blast cleaned and coated with an approved corrosion inhibitor, and the areas patched back with shotrete.

There are isolated areas of delamination and spalling of the bottom flanges of the beams where there is no shotcrete. These areas are also likely the result of corrosion of the reinforcing or prestressing strands and should be repaired as mentioned in the previous paragraph.

The existing FRP repairs to the beams appear to be in good condition and no deficiencies were observed while inspecting these elements. No repairs are recommended at this time.

The post-tensioning system appears to be functioning as intended, and only has isolated areas of deterioration. The small sections of the ducts remaining unwrapped near the anchorage assemblies should also be covered with an FRP wrap similar to the main portion of the ducts. This would conceal the missing grout port cap and remaining split in the ducts. Although no deficiencies were observed, the hole in post tensioning conduit on Beam #1 at mid-span of Span #8 should be plugged.

Areas of delamination and spalling of the protective shotcrete over the post-tensioning anchorages was observed. Since the configuration of these anchorages is unknown, we recommend removing the deteriorated shotcrete, inspecting the anchorage assembly for deterioration, cleaning the substrate, and applying a new shotcrete layer.

There are numerous areas of delamination and isolated spalling up to 1” deep with exposed reinforcing (stirrups) on the beam webs. This deterioration is the result of insufficient concrete cover. It is our opinion that repair of these areas is not necessary based on the life expectancy goals for this structure. However, if desired the exposed reinforcing could be blast cleaned and coated with a protective coating. In addition, several areas of delaminated shotcrete repairs were identified on the beam webs. Again, it is our opinion that repair of these areas is not necessary based on the life expectancy goals for this structure. However, if desired the shotcrete could be removed and any exposed reinforcing could be blast cleaned and coated with a protective coating.

Diaphragms:

There are random areas where the cast-in-place concrete closure pours at the ends of the beams are delaminated and spalled. Many of these areas have been repaired with concrete in the past; however, some of the repairs have since delaminated or spalled. These deficiencies occur beyond the back edge of the bearing pads and do not result in any loss of strength for the bridge. However, this does provide an opportunity for water, which can be wicked in along the strands and cause corrosion, to access the ends of the beams. To prevent this we recommend sealing the ends of the beams with epoxy.

SUBSTRUCTURE

Abutments:

Due to the cracking of the abutment elements and condition of existing epoxy covering, all concrete surfaces should be cleaned and recoated with epoxy to prevent future water infiltration. Prior to coating Abutment A with epoxy, the delaminated and spalled concrete on the Beam #1 bearing seat should be removed and any exposed rebar coated with an appropriate coating for steel. Coating the abutments with epoxy could potentially extend the bridge life span by eliminating the threat of future corrosion initiated by water leaching through cracks.

Cat creek is a slow moving tidal body of water and, consequently, the abutment foundations would not be expected to be undermined due to scour. However, some minor to moderate erosion does exist along the face of Abutment B should also be repaired to prevent further undermining of the footing or the exposure of any piles.

Abutment Slope Protection:

Overall, the slope protection at each abutment slope is in good condition, except for deficiencies at the base, along the waterline. There is a small erosion hole at the base of the slope at Abutment A (with some displaced slope protection blocks) and the bottom three rows of concrete slope protection blocks at Abutment B are displaced for full width of the slope protection. As mentioned above, the water flow beneath this structure is typically slow moving, so repair of these areas is not an immediate concern, but should be addressed at some point in the future.

Cylinder Piles:

Hairline vertical cracks typically extend from the top of the piles and are beginning to show through the current epoxy coating. Additionally, there are random areas of delamination and spalling with isolated section loss to exposed rebar and prestressing strands on the piles. These openings in the concrete need to be sealed to protect the rebar and prestressing strands. In the worst case scenario, deterioration within the piles could reach a point that reduces the overall compression strength of the piles. Therefore, the delaminated and spalled areas should be chipped away to sound concrete, then recast to original dimensions. Lastly, the top 8’ of the piles should be sealed with additional epoxy coating. Some delaminated and/or spalled concrete is located near the waterline, and should be coated with epoxy separately. Three total piles at Piers #10 and #11 have already been jacketed at the top, and do not require additional repairs.

Additional repairs per the most recent underwater inspection report include plugging the hole in the north pile at Pier #4, and replacing the epoxy on top of the low water pile jacket on the north pile at Pier #9. The repairs should be made for the same reasons stated above.

Pier Caps and Bearing Seats:

Typically, the ends of the pier caps are deteriorated, including cracking, efflorescence, rust stains, delamination, and spalling. These areas can probably be attributed to years of water leakage throughout the deck expansion joints and ponding on top of the caps. As with the piles, these cracked and spalled areas present an opportunity for salt and moisture from the coastal environment to infiltrate the concrete and corrode the steel reinforcing. Over time, this could lead to a loss of load carrying capacity or localized areas of severe corrosion below the exterior beams. The deteriorated concrete needs to be removed back to the limits of sound concrete, then recast to original dimensions. Any cracks larger than 1/16” wide need to pre-sealed or injected with epoxy, then the entire caps should be recoated with epoxy.

CHANNEL

Fender System:

The existing fenders system is much newer than the concrete bridge structure, and only has minor deficiencies at this time. However, the lower dolphin steel wire wraps should be replaced as mentioned in the most recent underwater inspection report.

APPROACHES

The unpaved strip of asphalt at the Abutment A approach remains rough and deteriorated. This section of asphalt could be milled and repaved to achieve a smoother transition, but given the posted speed at the structure (15/25 MPH), a noticeably reduced impact may not be accomplished by repaving the approach.

However, the older asphalt at both abutments should be sealed to prevent water freezing between the asphalt layers and breaking up the pavement. In addition, the approach header spalls at Abutment B should be repaired with concrete prior to resealing the expansion joint, similar to the top of deck.

The weight limit sign at the west approach is beyond repair and should be replaced in an effort to keep overweight trucks from crossing the structure without a permit.

CONCLUSION

Stated above are all the maintenance items and recommended repairs as a result of this inspection. Since some recommendations should be ranked higher than others, a prioritized list is shown below to distinguish the repairs needed to maintain this structure at its current capacity for an additional 10 to 15 years.

Contained within this list are measures that will also help prevent an interruption in service due to the possibility of severe localized deterioration in the future. An associated cost and quantity for each repair can be found later in the “COST ESTIMATE” section of this report.

This bridge is considered to be “Functionally Obsolete”, meaning that it does not meet current geometric standards. For instance, the travel lanes are only 10’ wide instead of the standard 12’ width, there are no shoulders, and the safety curb/parapet/railing system does not meet current safety standards. While this determination does not affect the load carrying capacity of the structure, it should be taken into account as critical repair/rehabilitation/replacement decisions are made in the future.

The following repairs are needed to extend the service life of this structure and should take priority over routine or preventative maintenance:

1. Replace the weight limit sign at the west approach.

2. Clean and reseal the deck expansion joints as needed (including sections within the curbs and parapets).

3. Repair areas of delamination and spalling extending into the prestressed beam bottom flanges (with or without the presence of shotcrete).

4. Continue wrapping the external post tensioning ducts in Spans #8 and #11 to the extent of the anchorage assemblies.

5. Remove the deteriorated shotcrete from the post tensioning anchorage assemblies in Span #8, then clean the substrate and apply a new layer of shotcrete.

6. Plug the hole in the post tensioning conduit on Beam #1 in Span #8, near mid-span.

7. Clean and seal the prestressed beam ends.

8. Repair areas of delamination and spalling in the pier caps.

9. Clean and seal the pier caps with epoxy.

10. Repair areas of delamination and spalling in the cylinder piles.

11. Plug hole in north pile at Pier #4 (per most recent underwater inspection report).

12. Clean and seal the top 8’ of cylinder piles with epoxy.

13. Replace epoxy at top of low water pile jacket on north pile at Pier #9 (per most recent underwater inspection report).

14. Clean and seal all concrete surfaces on the abutments with epoxy.

15. Repair areas of delamination in the deck surface (including deck headers and approach slab headers).

16. Clean and seal the entire deck surface.

17. Repair areas of delamination, honeycombing, and spalling in the deck underside.

18. Replace missing access panel screws in the curbs.

19. Clear the deck drains as needed.

The following repairs will not necessarily extend the life cycle of this structure, but should be addressed in the course of routine or preventative maintenance work:

1. Replace the utility hardware as needed and repair the sheathing for the water line on the south side.

2. Remove the vine growth from the deck underside in Span #1.

3. Repair the areas of delamination in the parapet and curbs in Spans #3 and #16.

4. Replace the missing railing toggle bolts, expansion sleeves, and end caps.

5. Repair the erosion of both abutment slopes, then replace the displaced blocks at the base of both slope protections.

6. Replace the lower dolphin steel wire wraps (per most recent underwater inspection report).

7. Seal the approach pavement along the backwall at both abutments.

COST ESTIMATE:

Listed below is a summary of the “Type of Work” required to remediate the deficiencies found during this inspection. The “Approximate Quantity” associated with each deficiency and an associated “Unit Cost” for each type of work is also listed.

Three repair scenarios have been outlined to help in the budgeting process. “Scenario A” includes recommended work that will ultimately extend the life cycle of the structure. “Scenario B” includes all recommended work described in this report, including routine and preventative maintenance, which should theoretically extend the life of the structure even longer. “Scenario C” includes estimated costs to replace the structure with a new structure containing two 12’ wide lanes, 10’ wide shoulders, and standard parapets, which would meet current geometric and functional standards.

Note that construction related costs can vary significantly depending on location, site conditions, local requirements, permits, and other fees. Additionally, these quantities are approximate and based on non-destructive inspection techniques. Often, during rehabilitation, the extent of deterioration discovered within concrete elements is more than anticipated. These costs estimates should be considered preliminary and used a guide only.

Structure: Wallops Island Causeway Bridge Date Inspected: October 6, 2016

SCENARIO A

Type of Work Approximate

Quantity Unit Cost Total Cost

Replace weight limit sign at west approach 1 EA Clean and reseal deck expansion joints

(including sections within curbs and parapets)

240 LF

Repairs areas of delamination and spalling in prestressed beam bottom flanges

210 SF

Continue wrapping external post tensioning ducts in Spans #8 and #11

105 LF

Remove/replace deteriorated shotcrete from post tensioning anchorages in Span #8.

10 SF

Plug hole in post tensioning conduit on Beam #1 in Span #8

LS

Clean and seal prestressed beam ends 750 SF Repair areas of delamination and spalling in pier caps 195 SF

Clean and seal pier caps with epoxy 7500 SF Repair areas of delamination and spalling in cylinder piles

20 SF

Plug hole in north pile at Pier #4 LS Clean and seal top 8’ of cylinder piles with epoxy 4200 SF

Replace epoxy at top of low water pile jacket on north pile at Pier #9

LS

Clean and seal all concrete surfaces at abutments with epoxy

1000 SF

Repair areas of delamination and spalling in deck surface (including deck headers and approach slab headers)

470 SF

Seal entire deck surface 28,240 SF Repair areas of delamination, honeycombing, and spalling in deck underside

60 SF

Replace missing access panel screws in the curbs LS Clear deck drains LS

Subtotal Mobilization LS

Maintenance of Traffic LS Environmental and Worker Protection LS

Engineering Services LS Contingency LS

Total

Structure: Wallops Island Causeway Bridge Date Inspected: October 6, 2016

SCENARIO B

Type of Work Approximate

Quantity Unit Cost Total Cost

Replace weight limit sign at west approach 1 EA Clean and reseal deck expansion joints

(including sections within curbs and parapets)

240 LF

Repairs areas of delamination and spalling in prestressed beam bottom flanges

210 SF

Continue wrapping external post tensioning ducts in Spans #8 and #11

105 LF

Remove/replace deteriorated shotcrete from post tensioning anchorages in Span #8.

10 SF

Plug hole in post tensioning conduit on Beam #1 in Span #8

LS

Clean and seal prestressed beam ends 750 SF Repair areas of delamination and spalling in pier caps 195 SF

Clean and seal pier caps with epoxy 7500 SF Repair areas of delamination and spalling in cylinder piles

20 SF

Plug hole in north pile at Pier #4 LS Clean and seal top 8’ of cylinder piles with epoxy 4200 SF

Replace epoxy at top of low water pile jacket on north pile at Pier #9

LS

Clean and seal all concrete surfaces at abutments with epoxy

1000 SF

Repair areas of delamination and spalling in deck surface (including deck headers and approach slab headers)

470 SF

Seal entire deck surface 28,240 SF Repair areas of delamination, honeycombing, and spalling in deck underside

60 SF

Replace missing access panel screws in the curbs LS Clear deck drains LS

Replace utility hardware and repair water line sheathing LS Remove vine growth from deck underside in Span #1 LS Repair areas of delamination in parapet and curbs in

Spans #3 and #16

40 SF

Replace missing railing toggle bolts, expansion sleeves, and end caps

LS

Repair erosion and displaced blocks in each abutment slope protection and erosion along face of Abutment B

10 CY

Replace the lower dolphin steel wire wraps LS Seal approach pavement along Backwalls 135 SF

Subtotal Mobilization LS

Maintenance of Traffic LS Environmental and Worker Protection LS

Engineering Services LS

Structure: Wallops Island Causeway Bridge Date Inspected: October 6, 2016

SCENARIO C

Type of Work Approximate

Quantity Unit Cost Total Cost

Removal of Existing Structure 35,000 SF Construction of Replacement Structure 61,000 SF

Subtotal Engineering Services LS